The present invention relates to compositions and methods for administering a hair growth promoter useful in the treatment of alopecia, as well as compositions and methods related to the stimulation of hair growth in animals.
Hair loss and baldness (alopecia) are common phenomena in mammals, including humans. (See, for example, A. G. Messenger (1993) J. Investing. Dermatol. 101:48-98; D. G. Brodland, S. A. Muller (1991) Cutis 47:173-176; J. R. Spindler, J. L. Data (1992) Dermatol. Nurs. 4:93-99; A. K. C. Leung, W. L. M. Robson (1993) J. Roy. Soc. Health 113:252-256). Hair loss is an extremely common condition in healthy adult male humans, and also occurs frequently in adult female humans. In fact, some degree of alopecia on the vertex from puberty onwards is thought to be a universal phenomenon in both men and women (R. P. R. Dawber (1987) Dermatologica 175:23-28).
Hair loss may be naturally occurring (primary alopecia) or it may be induced by chemical or physical agents (secondary alopecia). (See, for example, M. B. Brodin (1987) Dermatol. Clin. 5:571-579; A. Tosti, et al. (1994) Drug Saf. 10:310-317; H. J. Carson, et al. (1994) J. Cutan. Pathol. 21:67-70). Alopecia is also frequently observed in both pre- and post-pubertal patients as a side effect of anti-cancer chemotherapy (A. M. Hussein, et al. (1990) Science 249:1564-1566; B. W. Cline (1984) Cancer Nursinz 7:221-228; A. F. Hood (1986) Med. Clin. North Am. 70:187-209). Hair loss may also result from specific disease states, such as mange, or formation of scar tissue from bites and with increasing age. (D. A. Mehregan, et al. (1992) J. Am. Acad. Dermatol. 27:935-942; D. A. Slagle, T. A. Martin (1991) Am. Fam. Physician 43:2019-2024; L. V. Spencer, J. P. Callen (1987) Dermatol. Clin. 5:565-570).
The physical phenomenon of hair loss may lead to psychological problems in the patient, decreased social activity, and the development of psychological diseases. In the case of cancer patients, the likelihood of chemotherapy-induced alopecia may lead to a refusal to accept treatment. As a result of the prevalence of alopecia, and its potentially devastating impact, there is immense interest in the development of effective clinical treatments, both to prevent hair loss and to stimulate regrowth of lost hair.
Despite the widespread occurrence of alopecia, the need for prevention and therapy, and extensive research efforts to find suitable remedies, there remains an urgent need for effective treatment. For example, lack of a proven and effective treatment for alopecia has caused many afflicted individuals to adopt the practice of wearing a wig or toupee. Another extreme measure used to combat alopecia, hair transplant surgery, is not available as an option in many cases, e.g., following chemotherapy, and offers, at best, only a partial remedy.
A common non-surgical treatment for stimulating hair growth which is currently used clinically is minoxidil (The Upjohn Company, Kalamazoo, Mich.). A solution of minoxidil as active ingredient is known as Rogain(copyright). As stated in the Rogaine(copyright) Patient Information Booklet (The Upjohn Company, Kalamazoo, Mich., revised June, 1992) minoxidil is a vasodilatory drug which has serious side effects when administered orally for the treatment of hypertension. At the same time, topical application of minoxidil for the treatment of alopecia is only partially effective and suffers from a number of disadvantages. For example, it is only recommended for treatment of male pattern alopecia of the vertex (of frontal recession), has to be applied twice daily for at least four months, and requires a normal scalp with no local abrasions, dermatitis or sunburnxe2x80x94conditions that can increase absorption into the blood stream and the concomitant risk of side effects. Further, minoxidil is of limited effectiveness insofar as for those patients who do respond to minoxidil treatment, the new hair is likely to be shed within a few months after stopping treatment.
Moreover, it is recognized that delivering such active ingredient or ingredients through the skin, i.e., transdermally, as opposed to other methods of parenteral administration is extremely difficult. In this regard, in order to be effective, an active agent for hair treatment must pass through the outer layer of skin or epidermis and into the dermis layer before being absorbed into the bloodstream. The epidermis comprises two main parts, the stratum corneum and the stratum germinativum. The stratum corneum forms the outermost layer of the epidermis and consists of many stratified layers compacted, flattened, keratinized cells which have lost their nuclei. This outermost layer serves as a physical barrier to microorganisms and also to chemical agents. In particular, it behaves as a primary barrier to percutaneous absorption of drugs. Because of the barrier effect of the skin, it has heretofore only been possible to deliver drugs that are xe2x80x9clow-dosexe2x80x9d drugs, i.e. in the range of 15 mg/day or less, or those of low molecular weight. In addition, drugs for transdermal delivery must have the proper lipophilic-hydrophilic balance to permit adequate absorption. As early as the beginning of the twentieth century it has been known that lipid-soluble substances, such as non-electrolytes, have a comparatively greater skin permeability than water-soluble substances, such as electrolytes.
Recently, an orally-administered systemic agent, namely, finasteride, sold under the trademark Propecia(copyright) produced by Merck and Company of West Point, Penn., has proven clinically effective in treating alopecia in men with male pattern hair loss (androgenetic alopecia). Propecia(copyright) is a competitive and specific inhibitor of Type II 5xcex1-reductase, an intracellular enzyme that converts the androgen testosterone into DHT. Administration of Propecia(copyright) decreases scalp and serum DHT concentrations and, by this mechanism, appears to interrupt the enzymatic pathway attributable to the development of androgenetic alopecia in those patients genetically predisposed to such condition.
While clinically effective in treating male pattern hair loss, Propecia(copyright) is known to produce significant adverse reactions. These adverse reactions include sexual dysfunction, as well as reported incidences of breast tenderness and enlargement. This composition is further extremely teratogenic and must not be handled by pregnant women insofar as Propecia(copyright) is suspected of causing impaired sexual organ development in male fetuses.
Accordingly, there is substantial need in the art for not only compositions that are effective at stimulating hair growth, but are further effective at transdermally delivering hair growth promoters useful in the treatment of alopecia. There is further a need in the art to provide a treatment for hair loss and compositions for delivering hair growth promoters useful in treating hair loss that are safe, simple, easy to apply and relatively inexpensive when compared to other hair loss treatments. There is a further need in the art to provide a treatment for hair loss that provides faster and more abundant hair regrowth than conventional treatments that additionally utilizes all natural ingredients that are non-toxic.